Wednesday, August 18, 2010

Younger Canadians have more BPA in their bodies than parents: Study

Canadian children and teenagers have higher levels of bisphenol A in their urine than their parents and grandparents, according to the government's first-ever national survey on the exposure of chemicals — which also found that nearly all Canadians have the estrogen-mimicking toxin in their bodies.

The Statistics Canada study, conducted in partnership with Health Canada, found that nine out of 10 Canadians aged six to 79, or 91 per cent of the population, have BPA in their urine. But young people aged 12 to 19 had an average level of 1.50 parts per billion — higher than the overall average of 1.16 parts per billion.

Younger children also brought up the national average (1.30 ppb), while their parents (ages 40 to 59) and their grandparents (ages 60 to 79) had lower levels of the toxin (1.04 and 0.90 ppb respectively) in their urine.

Given how quickly BPA can be flushed from the body and the high frequency of detection, "these data suggest continual and widespread exposure of BPA," states the report, released Monday.

Bisphenol A can leach into food from the protective epoxy resin coatings of canned foods or beverages and from such consumer products as polycarbonate tableware, plastic food storage containers and reusable hard plastic bottles.

Lead author Tracey Bushnik, of Statistics Canada's health analysis division, said the study could not determine why young Canadians have higher levels of BPA in their urine, but suggested a combination of forces could be at work.

"Children have a different physiology compared to adults. For example, how they absorb or distribute or metabolize or excrete BPA could be different," said Bushnik. "How they're using products containing BPA (or) how many products containing BPA they could be using, that could be another factor."

The report said it can't make a finding on safety because the government has yet to establish a level of BPA in urine that would be of concern — although Health Canada has a safe intake level for the substance.

"Although BPA may constitute a health risk, no guidance values are currently available in Canada for urinary BPA," states the technical report on the first cycle of the Canadian Health Measures Survey, an ongoing probe of approximately 5,600 Canadians aged six to 79 involving home interviews and physical tests.

Reproductive toxicity — including effects on fertility and development — has been identified as a key health effect of exposure to high concentrations of BPA, a recognized endocrine disrupter.

The U.S. government's national toxicology program, meanwhile, has concluded it has "some concern for effects on the brain, behaviour and prostate gland in fetuses, infants and children at current human exposures to bisphenol A."

The American Chemistry Council, which recently set back in its bid to block Ottawa from listing BPA as a toxic substance in Canadian law, was quick to characterize the results as "very reassuring," saying the typical level of BPA found in urine corresponds to an intake that is approximately 1,000 times below the safe intake level set by Health Canada for all age groups — including children and teenagers.

But consumer advocacy groups read the results differently, saying they illustrate why Canada's 2008 ban of BPA in plastic baby bottles needs to be extended to other products, including tin cans for food and drinks.

"I don't care what kind of outdated, half-baked argument the industry tries to muster today. There's no way they can explain away any level of a hormonally active chemical in nine out of 10 Canadians. It's just not possible," said Rick Smith, executive director of Environmental Defence.

"The reality is that the best available science points to the fact that there is no safe level of BPA — that any amount of BPA has some biological effect, as you would expect from a hormonally active chemical."

He added that the BPA "trend line" is moving in the wrong direction.

"Kids have higher BPA levels in their bodies than the parents and grandparents do. And that means that the kind of leadership the Canadian government has undertaken on BPA needs to continue. What we need to see is BPA banned and regulated in the other areas where it's present in our daily lives."

A spokesman for Health Minister Leona Aglukkaq declined to say whether she was concerned about the results, but said the government "will continue to take action where needed."

The survey also tested for lead levels in the blood of Canadians. Lead was detected in 100 per cent of the population, but concentrations have fallen dramatically in the past 30 years and now stand below levels that would require intervention for more than 99 per cent of the population.

Thirty years ago, more than one in four Canadians — or about 27 per cent — had blood-lead concentrations at or above the intervention level, set at 10 micrograms per decilitre. Today, the average is 1.34 micrograms per decilitre.

Unlike the case with BPA, the survey shows that older Canadians have the highest levels of lead in their blood.

"The lead and BPA results are a study in contrasts," said Smith. "It confirms the good news about lead. When governments get their act together and regulate these kinds of chemicals, you see important public health benefits."


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